1. Technical Field
The invention relates to the compositions consisting of chlorine-containing polymers and cyanoacetylureas which are of the formula I depicted below and are intended for stabilizing these polymers, especially PVC.
2. Prior Art
PVC can be stabilized by a range of additives. Compounds of lead, of barium and of cadmium are particularly suitable for this purpose but are nowadays controversial on ecological grounds or because of their heavy metal content (cf. "Kunststoffadditive", R. Gachter/H. Muller, Carl Hanser Verlag, 3rd ed., 1989, pages 303-311, and "Kunststoff Handbuch PVC", volume 2/1, W. Becker/D. Braun, Carl Hanser Verlag, 2nd ed., 1985, pages 531-538; and also Kirk-Othmer: "Encyclopedia of Chemical Technology", 4.sup.th ed., 1994, Vol. 12, Heat Stabilizers, pp. 1071-1091). The search therefore continues for effective stabilizers and stabilizer combinations which are free from lead, barium and cadmium.
Some of the compounds of the formula I are novel substances while others are known. Representatives of the formula I have been described, for example, in U.S. Pat. No. 2,598,936 and J. Org. Chem. 16, 1879-1890 (1951) and can be prepared by known methods in one or more process steps. The initial ureas are obtainable commercially or can be prepared by known methods.